After decades of lawsuits, public campaigns and painful struggles, Americans have finally done what once seemed impossible: Most of the country has quit smoking, saving millions of lives and leading to massive reductions in cancer.

That is, unless those Americans are poor, uneducated or live in a rural area.

Hidden among the steady declines in recent years is the stark reality that cigarettes are becoming a habit of the poor. The national smoking rate has fallen to historic lows, with just 15 percent of adults still smoking. But … among the nation’s less-educated people — those with a high-school-equivalency diploma — the smoking rate remains more than 40 percent …

Today, rural residents are diagnosed with lung cancer at rates 18 to 20 percent above those of city dwellers. By nearly every statistical measure, researchers say, America’s lower class now smokes more and dies more from cigarettes than other Americans.